Metal disintegrators have been used for decades to cut metal components that, typically, are too hard, inaccessible or otherwise impractical for more conventional cutting techniques such as drilling, milling, sawing, abrading or oxygen acetylene torching. Metal disintegrators vibrate a graphite electrode into and out of contact with a metal part to be cut. Electrical current supplied at the cutting end of the electrode turns local areas of the part being cut molten and water or other liquid coolant solidifies and fractures the local molten areas into small free particles when the electrode cyclically pulls away from the part. The process cycles many times a second, e.g. 60 or 50 Hz until a cut is completed to the desired depth.
When parts of large cross-section are to be severed from a surrounding body such as a stud locked in a hole, it is known to use a tubular electrode having an outside diameter slightly smaller than the stud. The electrode is used to burn through the operative length of the stud leaving a disembodied core. This technique greatly reduces the total energy required for burning the stud free of its surrounding solid compared to what would be required if a solid or coreless electrode was used. In practice, tubular electrodes of the prior art experience limitations in the size or included cross-section and length or depth of a cut. Beyond certain electrode included cross-section size and length combinations, cutting action is slowed or eventually stopped and accuracy is compromised or lost.